Unexplained bruising

Causes of unexplained bruising and when you should see your doctor

Bruises can often appear on our skin and sometimes we can forget what has caused them. Some people, such as the very young or the very old, are more susceptible to bruising, meaning that contusions are a common occurrence. In this page, our muscle and joint expert Earle Logan explores the possible causes of unexplained bruises and recommends when you should seek out your doctor.

An introduction to unexplained bruises

Bruises are small collections of blood in the tissues just under the skin. They result from injury or trauma causing damage to the small blood vessels lying close to the surface of the skin. Blood leaks out and spreads through the surrounding tissue.

Bruises appear initially as dark red patches and as they resolve, become purple, green or yellow in colour. If enough blood accumulates, bruises may also be associated with swelling under the skin.

We often injure ourselves without being aware of the incident and because of this, unexplained bruising is very common. Even a small knock can cause a little internal bleeding and a bruise, and when repeated, may result in bruises that we can’t even remember the cause of, especially if one is particularly active.